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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Post-test data report for the space shuttle full-scale AFRSI sequence of environments test (OS-305-1 to -5) in the NASA/Ames Research Center 11x11-foot wind tunnel

The Advanced Flexible Reusable Surface Insulation (AFRSI) test article was wind tunnel tested. The AFRSI was exposed to a simulated ascent airloads environment and data was obtained which could be used to support the AFRSI certification program. The AFRSI sequence of environments also included radiant heating (1500 degrees Fahrenheit) and wind/rain environments. The test article was wind/rain conditioned before each wind tunnel entry and was thermally conditioned after each wind tunnel entry. The AFRSI failed and the test was aborted before reaching the ascent environment. The AFRSI test article sequentially exposed to 50 wind/rain and 49 simulated entry thermal missions, as well as four wind tunnel entries equivalent to 40 ascent missions.

Marshall, B. A.↗
NASA NTRS1984

Space Environment Effects on Spacecraft Materials (M0003)

The immediate objectives of this experiment are to understand changes in the properties and structure of materials after exposure to the space environment and to compare these changes with predictions based on laboratory experiments. The experiment consists of 19 subexperiments involving a number of DOD laboratories and contractor organizations. In general, the experimental approach with each of the subexperiments will involve comparison of preflight and postflight analyses. Typical analyses will include the measurement of optical properties (reflectance, transmittance, and refractive index), and macrophysical properties. In addition to measuring changes in the macroscopic properties of the returned specimens, microstructural properties will also be examined. Thus, it may be possible to increase our understanding of the changes induced by the environment. This increased understanding can then be used to predict the performance of materials based on knowledge of the space environment and the results of laboratory tests. This experiment will be a coopperative effort and will provide an opportunity for DOD space programs and laboratories to evaluate materials and components after long exposures to the space environment.

Paul Schall↗
NASA NTRS1983

Spacecraft contamination environment; Proceedings of the Meeting, Arlington, VA, May 4-6, 1982

Aspects of IECM debriefing are considered, taking into account preliminary results of the induced environment contamination monitor measurements of STS-2, the humidity monitor and dew point hygrometer, the induced environment contamination monitor cascade impactor, the optical effects module and passive sample array, temperature-controlled quartz crystal microbalance measurements on STS-2, camera/photometer results, the mass spectrometer, and a summary regarding the induced environment contamination monitor/space transport system. Other subjects explored are related to contamination management and control, contamination/optical degradation, and contamination assessments and measurements. Attention is given to approaches for controlling contamination before launch, the coronagraph as the ultimate device to monitor orbiting particulates in the Space Transport System environment, and the contamination sensitivity of typical mirror coatings.

Maag, C. R.↗
NASA NTRS1984

An evaluation of grease type ball bearing lubricants operating in various environments

Because many future spacecraft or space stations will require mechanisms to operate for long periods of time in environments which are adverse to most bearing lubricants, a series of tests has been completed to evaluate 38 grease type lubricants in R-4 size bearings in five different environments for a 1 year period. Four repetitions of each test were made to provide statistical samples. These tests were also used to select four lubricants for 5 year tests in selected environments with five repetitions of each test for statistical samples. In this completed program, 172 test sets have been completed. The three 5 year tests in: (1) continuous operation and (2) start stop operation, with both in vacuum at ambient temperatures, and (3) continuous vacuum operation at 93.3 C have been completed. In both the 1 year and 5 year tests, the best results in all environments have been obtained with a high viscosity index perfluoroalkylpolyether (PFPE) grease.

Mcmurtrey, E. L.↗
NASA NTRS1984

Effects of the Solar and Extraterrestrial Environments on Space Power Systems

Environments surrounding the major extraterrestrial bodies in the solar system and their interactions with spacecraft power systems are summarized. The environments associated with neutrals/dust, low energy plasma, and where applicable, magnetospheres are discussed for a wide variety of cases. The impact of these environments on power systems - in particular, radiation effects, spacecraft charging, plasma interactions, surface sputtering/erosion, and induced currents - are presented. As power systems must be designed to survive in these hostile environments, it is important that they be taken into account in planning future power systems.

Garrett, H. B.↗
NASA NTRS1985

Natural environment design criteria for the Space Station definition and preliminary design

The natural environment design criteria for the Space Station Program (SSP) definition and preliminary design are presented. Information on the atmospheric, dynamic and thermodynamic environments, meteoroids, radiation, magnetic fields, physical constants, etc. is provided with the intension of enabling all groups involved in the definition and preliminary design studies to proceed with a common and consistent set of natural environment criteria requirements. The space station program elements (SSPE) shall be designed with no operational sensitivity to natural environment conditions during assembly, checkout, stowage, launch, and orbital operations to the maximum degree practical.

Vaughan, W. W.↗
NASA NTRS1985

Long term evaluation of grease type lubricants in selected environments

The operating life of grease-type lubricants in various environments is evaluated. The test equipment and procedures are described. The lubricants were placed in the rolling element bearings of hysteresis synchronous motors and exposed to environments of a vacuum at 60 C, a vacuum at 93.3 C, 10 psia oxygen at 90 percent relative humidity at 60 C, 14.7 psia air at 90 percent relative humidity at 60 C, start-stop operation, and low temperature start capability for one or five years. The weights of the bearings were measured before and after lubrication; the weight data for each environment are analyzed. The data reveal that the high viscosity index perfluoroalkypolyether grease performs the best in a vacuum at moderate and high temperature, in low temperature start capability, and in start-stop steps; however, the grease does not work well in oxidizing and high relative humidity environments.

Dolan, F. J.↗
NASA NTRS1985

Calculation and use of an environment's characteristic software metric set

Since both cost/quality and production environments differ, this study presents an approach for customizing a characteristic set of software metrics to an environment. The approach is applied in the Software Engineering Laboratory (SEL), a NASA Goddard production environment, to 49 candidate process and product metrics of 652 modules from six (51,000 to 112,000 lines) projects. For this particular environment, the method yielded the characteristic metric set (source lines, fault correction effort per executable statement, design effort, code effort, number of I/O parameters, number of versions). The uses examined for a characteristic metric set include forecasting the effort for development, modification, and fault correction of modules based on historical data.

Basili, Victor R.↗
NASA NTRS1987

The PISCES 2 parallel programming environment

PISCES 2 is a programming environment for scientific and engineering computations on MIMD parallel computers. It is currently implemented on a flexible FLEX/32 at NASA Langley, a 20 processor machine with both shared and local memories. The environment provides an extended Fortran for applications programming, a configuration environment for setting up a run on the parallel machine, and a run-time environment for monitoring and controlling program execution. This paper describes the overall design of the system and its implementation on the FLEX/32. Emphasis is placed on several novel aspects of the design: the use of a carefully defined virtual machine, programmer control of the mapping of virtual machine to actual hardware, forces for medium-granularity parallelism, and windows for parallel distribution of data. Some preliminary measurements of storage use are included.

Pratt, Terrence W.↗
NASA NTRS1986

Scientific computing environment for the 1980s

An emerging scientific computing environment in which computers are used not only to solve large-scale models, but are also integrated into the daily activities of scientists and engineers, is discussed. The requirements of the scientific user in this environment are reviewed, and the hardware environment is described, including supercomputers, work stations, mass storage, and communications. Significant increases in memory capacity to keep pace with performance increases, the introduction of powerful graphics displays into the work station, and networking to integrate many computers are stressed. The emerging system software environment is considered, including the operating systems, communications software, and languages. New scientific user tools and utilities that will become available are described.

Bailey, F. R.↗
NASA NTRS1986

Assessment of space environment induced microdamage in toughened composite materials

The effects of simulated space environments on the microdamage in a series of commercially available toughened matrix composite systems was determined. Low-earth orbit (LEO) exposures were simulated by thermal cycling; geosynchronous orbit (GEO) exposures were simulated by electron irradiation plus thermal cycling. Material response was characterized by assessing the induced microcracking and its influence on chemical and mechanical property changes. All materials, including several advanced, tough thermoplastics microcracked when exposed to the simulated LEO environment except a 177 C cured single phase toughened epoxy composite. The GEO simulated environment produced microdamage in all materials. The results suggest that increased matrix toughness may not be the overriding factor leading to improved durability in the space environment.

Sykes, George F.↗
NASA NTRS1988

An intelligent processing environment for real-time simulation

The development of a highly efficient and thus truly intelligent processing environment for real-time general purpose simulation of continuous systems is described. Such an environment can be created by mapping the simulation process directly onto the University of Alamba's OPERA architecture. To facilitate this effort, the field of continuous simulation is explored, highlighting areas in which efficiency can be improved. Areas in which parallel processing can be applied are also identified, and several general OPERA type hardware configurations that support improved simulation are investigated. Three direct execution parallel processing environments are introduced, each of which greatly improves efficiency by exploiting distinct areas of the simulation process. These suggested environments are candidate architectures around which a highly intelligent real-time simulation configuration can be developed.

Carroll, Chester C.↗
NASA NTRS1988

Process migration in UNIX environments

To support process migration in UNIX environments, the main problem is how to encapsulate the location dependent features of the system in such a way that a host independent virtual environment is maintained by the migration handlers on the behalf of each migrated process. An object-oriented approach is used to describe the interaction between a process and its environment. More specifically, environmental objects were introduced in UNIX systems to carry out the user-environment interaction. The implementation of the migration handlers is based on both the state consistency criterion and the property consistency criterion.

Lu, Chin↗
NASA NTRS1988

The concurrent common Lisp development environment

A discussion of the Concurrent Common Lisp Development Environment on the iNTEL Personal Super Computer (iPSC) is presented. The advent of AI based engineering design tools has lead to a need for increased performance of computational facilities which support those tools. Gold Hill has approached this problem by directing its efforts to the creation of a concurrent, distributed AI development environment. This discussion focuses on the development tools aspect of the CCLISP environment. The future direction of Gold Hill in the area of distributed AI support environments is also presented.

Source record↗
NASA NTRS1988

Performance of multimirror quartzline lamps in a high-pressure, underwater environment

Multimirror Quartzline Lamps are extremely versatile and effective for nonconventional imaging requirements such as high-speed photo and video instrumentation and high-magnification imaging. The lamps' versatility though, is not limited to conventional environments. Many research experiments and projects require a high pressure environment. Continuous photographic data acquisition in a high-pressure vessel requires wall penetrations and creates design problems as well as potential failure sites. Underwater photography adds the extra consideration of a liquid. This report expands upon the basic research presented in, Performance of Multimirror Quartzline Lamps in High-Pressure Environments, (NASA-TM-83793, Ernie Walker and Howard Slater, 1984). The report provides information to professional industrial, scientific, and technical photographers as well as research personnel on the survivability of lighting a multimirror quartzline lamp in a nonconventional high-pressure underwater environment. Test results of lighted ELH 300 W multimirror quartzline lamps under high-pressure conditions are documented and general information on the lamps' intensity (footcandle output), cone of light coverage, approximate color temperature is provided. Continuous lighting considerations in liquids are also discussed.

Slater, Howard A.↗
NASA NTRS1989

Surface phenomena in plasma environments

Plasma interactions and their effects on materials depend on a number of factors, including the pre-existing environment, the properties of surface materials and the characteristics of the system. An additional dimension is the question of mission: some payloads may be much more sensitive to plasma interactions than others. As an example, a payload whose objective is to measure the ambient environment will be more sensitive to any effects than will a power system. Material specific effects include charging and its associated effects, which can result in short- and long-term damage. Selection of materials for a particular application requires consideration of all factors and assessment of effects due to all causes. Proper selection and suitability determination requires analysis to identify the actual environment combined with testing under exposure to single and combined environment factors.

Purvis, C. K.↗
NASA NTRS1988

Industrial applications of the microgravity environment

Opportunities for commercialization of the microgravity environment will depend upon the success of basic research projects performed in space. Significant demands for manufacturing opportunities are unlikely in the near term. The microgravity environment is to be considered primarily as a tool for research and secondarily as a manufacturing site. This research tool is unique, valuable, and presently available to U.S. investigators only through resources provided by NASA. The United States has an obligation to facilitate corporate research, maintain a flexible international policy, foster use of and assure access to a wide variety of facilities, and develop a posture of national and international leadership in and stewardship of research and materials processing in the microgravity environment. The National Research Council's Committee on Industrial Applications of the Microgravity Environment recommends six actions that strengthen this posture, including the formation of an authoritative organization to oversee the implementation of a program of microgravity research and its industrial applications.

Source record↗
NASA NTRS1988

The induced environment around Space Station

The potential impact of the International Space Station on its immediate environment is discussed, summarizing the results of recent investigations by NASA working groups. Consideration is given to the neutral-gas environment, induced photon emission, particulate contamination, the ionized environment, the Induced-environment Monitoring Package proposed for inclusion in the Space Station equipment, and recommendations for further research. Diagrams, drawings, graphs, and tables of numerical data are provided.

Torr, Marsha R.↗